Research in SWL conducted over the past ten years has shown that stresses sufficient to induce both fragmentation and cellular-level tissue damage can result from direct interaction with the focusing shockwave as well as secondary stresses induced by the expansion and collapse of cavitation bubbles. The proposed research will provide a detailed modeling and simulation of the fluid and solid-dynamical processes that occur both in vitro and in vivo during SWL. The specific aims are: 1. Modeling and computer simulation of the stresses acting on stones and soft tissue that results from the focusing shockwaves and clouds of cavitations bubbles in the fluid state. 2. Computer simulation of the dynamic fracture and fragmentation process in realistic stone models, including tracking the origin and propagation of each fracture. 3. Quantitative assessment of soft tissue damage in anatomically correct finite element models kidneys and individual structures therein. The modeling effort is closely guided by the extent and nature of the experimental evidence, available from close collaboration with the Program Project Group, that can be used to calibrate and validate the models. These data include quantitative assessment of kidney geometry and damage through digital images from a computer segmentation of pig kidneys, detailed pressure hydrophone measurements in vitro and in vivo, ultra-high-speed photography of bubble clouds and shockwaves, data on stone fragmentation, mechanical testing of strain-rate dependent material behavior, and ultrasound tomography of the structure and fracture of stones. Impact on clinical application will be maximized by working toward an integrated simulation facility capable of full-scale analysis of anatomically and mechanically correct models of stone comminution and tissue injury. The simulation facility will allow unprecedented predictive power that may ultimately show how to pulverize stones with fewer shocks and less renal injury.